I am a newbie to this whole idea of working with audio systems but I just need to ask a question.

A while ago, a couple of my friends bought a small place to set up as a new worship center. The place used to be a bank formerly and it came with the standard announce system that you find in a bank - which is in no way shape or form designed for any singing or anything else aside from announcing people's names. It probbably has just a few regular 40 watt speakers that you would expcet on such a system.

My question: If someone wants to upgrade that announce system into a system which has good sound for singing, what are the factors that one has to consider in terms of doing the upgrade. I am a complete newbie and really have no idea when it comes to anything related to sound...any advice/ input is much apprechiated....